1. Field of the Invention
The invention is directed to a flexible urethane coated and/or laminated textile material for use particularly in the manufacture of rainflies for military tents, and for rainflies made from such material. More specifically, the invention relates to reversible lightweight urethane coated and/or laminated fabrics which meet predetermined levels of opacity, ultra-violet protection, flame retardancy, cold weather crack resistance, mildew resistance, abrasion resistance, and infra-red reflectance within specified wavelengths when either fabric side is facing outwardly, and for methods of making the fabric.
2. Description of the Prior Art
Rainflies are often used over the top of conventional-type tents to form what are commonly known as double-walled systems. Such flies are adapted to add protection from driving wind and/or rain for all the openings of the tent, in addition to providing supplemental shelter or storage space. Currently, members of the military are required to have several differently colored rainflies in order to provide inconspicuous shelter in different environments. (For purposes of this application, the term "color" is meant to encompass black and white as well as other traditional colors.) For example, military rainflies are generally available in camouflage, white for arctic conditions, green for tropical conditions, and tan for desert regions. In addition to providing protection from wind, such rainflies must be waterproof, flame-retardant, cold weather crack resistant, mildew resistant, abrasion resistant, meet a predetermined visual shade requirement, provide a high degree of visual opacity (i.e. ability to "black out" light from the interior of the tent) and provide a degree of infrared reflectance within specified wavelengths. Furthermore, because military personnel are often forced to transport their equipment, it is necessary that the weight of such rainflies be minimized. Several rain fly and tent fabrics are described in U.S. Pat. No. 4,594,286 to McKinney et al., U.S. Pat. No. 4833,006 to McKinney et al., and U.S. Pat. No. 4,308,882 to Pusch et al., the disclosures of which are incorporated herein by reference.
Prior art rainflies generally include a polyurethane coating which is either clear or colored to match the ground fabric. Other rainflies for use in arctic environments have been made using a black ground fabric in combination with a white coating, with the black ground fabric being designed to help provide the requisite opacity to the white structure. However, heretofore rainflies have only been designed to provide the requisite opacity, visual color and IR characteristics on a single side. As a result, military personnel are often required to be equipped with two or more such rainflies, when they are expected to encounter more than one environmental condition (e.g. where they are to be dispatched to a region having both snowy areas and woodsy areas.) Because it is generally desirable to minimize a soldier's load to the extent possible, having to carry more than one rainfly to anticipate and be able to respond to varying climactic conditions can add undesirably to the bulk and weight of a soldier's load.
Conventional one-sided fabrics generally utilize a ground fabric having a coated weight varying from about 2.5 to 4.5 oz per square yard. In such products, it is generally the coated side of the fabric which provides the requisite physical characteristics.